This invention relates to a method/apparatus of casting multi-colored parts, and the product produced therefrom, particularly suitable for automotive interior applications, wherein said product provides a distinct two-tone color line to a vehicle occupant.
Different methods are known for casting multi-colored parts. One generic method involves simultaneous casting of multiple powdered materials. For a particular version of this method, a material supply box is divided into multiple chambers by virtue of a divider panel which separates or bisects multicolored materials. A gasket which interacts with the mold surface may be attached to the divider panel. Upon casting, the gasket, by virtue of interacting with the mold surface, forms a seal between the respective chambers of the material supply box. Upon removal of the material supply box and gasket, a gap exists between the portions of the casting previously occupied by the gasket. This gap, or joint line, may be filled by spraying additional materials on the area.
A second generic method may also be utilized which involves sequential casting of multiple powdered materials. For a particular version of this method, a mask or divider panel may be applied to a portion of the mold surface while another portion of the mold surface remains exposed. During the first casting, material is applied to the exposed area of the mold surface. The mask or divider panel is then removed and a second material, usually from a second material supply box, is applied to the mold surface previously occupied by the mask. Further, the second cast material may overlap the first cast material either partially or completely.
The following patents were uncovered in a search of the prior art.
All of the art noted above describes or depicts a gasket which, when used, moves into contact with the mold surface, then away from contact with the mold surface. The art therefore does not describe, teach or suggest a gasket which moves laterally on the mold surface to refine a joint line. Furthermore, the joint line created above is often refined after molding by post painting.
Attention is also directed to U.S. Pat. Nos. 5,525,274, 5,525,284 and 5,654,102 which are directed to a thermoplastic microsphere for use in roto-casting or slush molding of shells. In addition, attention is also directed to U.S. Pat. No. 5,998,030 which describes spherical particles having a diameter between 0.007xe2x80x3-0.040xe2x80x3 formed from melt extruded thermoplastic material formed of a blended and melt extruded thermoplastic along with pigment. In addition, attention is directed to U.S. Pat. No. 5,824,738 which relates to an improved light stable aliphatic polyurethane composition suitable for use as an automotive trim component.
In connection with the above art, similar to the above, although such microspheres have been employed to manufacture thin plastics shells or skins, again, there have been no reports of employing such microspheres and the advantages therein for the prepare a synthetic skin product with a two-tone or multi-tone color pattern.
Accordingly, one principal objective of the invention herein is to manufacture a two-tone article employing the use of spherical particles having a diameter between 0.007-0.040xe2x80x3. In addition, it is also an objective of the invention herein is to create a distinct two-tone color line in a vehicle, during casting, eliminating any need to post paint.
More specifically, it is also an objective of the invention herein to develop a casting technique in a powder slush molding process by use of a side-to-side sweeping motion of a bisection gasket which therein provides a crisp two-tone cast line in the final molded part.
In a first embodiment, the present invention comprises a method for making a joint line in a plastic article comprising the steps of providing a mold having a mold surface, providing a gasket in said mold wherein said gasket defines first and second mold spaces and molding a layer of a plastic material within one of said mold first and second mold spaces and laterally moving said gasket relative to said mold surface in a direction towards said mold space containing said plastic material during molding to therein form said joint line.
In a second embodiment, the present invention relates to a method for making a molded two-colored article comprising the steps of providing a mold having a mold surface, providing a gasket in said mold wherein said gasket defines first and second mold spaces, molding a layer of a first colored material within one of said mold first and second mold spaces wherein said first colored material comprises a charge of plastic microspheres, said microspheres having an outside diameter in the range of 0.007xe2x80x3 to 0.040xe2x80x3, and removing said gasket and molding a layer of a second colored material.
In a third embodiment, the invention herein relates to a method for making a molded two-colored article comprising the steps of providing a mold having a mold surface, providing a gasket in said mold wherein said gasket defines first and second mold spaces, molding a layer of a first colored material within one of said mold first and second mold spaces, and laterally moving said gasket relative to said mold surface in a direction towards said mold space containing said first colored material.
In apparatus form, the present invention relates to an assembly for molding a plastic shell in an open-ended mold from a charge of polymeric resin material, said assembly comprising an open-ended mold having a mold surface, a charge box adapted to be connected to said open-ended mold to form a closed system for molding said polymer resin material and having a gasket therein establishing first and second mold spaces, wherein said gasket is laterally movable relative to said mold surface in a direction into one of said first or second mold spaces.